mm/memory: remove PageAnonExclusive sanity-check in restore_exclusive_pte()

In commit b832a354d787 ("mm/memory: page_add_anon_rmap() ->
folio_add_anon_rmap_pte()") we accidentally changed the sanity check to
essentially ignore anonymous folio by mis-placing the "!" ...  but we
really always only get anonymous folios in restore_exclusive_pte().

However, in the meantime we removed the separate "writable
device-exclusive entries" and always detect if the PTE can be writable
using can_change_pte_writable() -- which also consults PageAnonExclusive.

So let's just get rid of this sanity check completely.

Link: https://lkml.kernel.org/r/20250226132257.2826043-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 26ba5a238d4502ce0a51da2847ccc99dae4c5fce..17ac1f9e2aa28ac6b16a33b5151543811b6c339b 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -740,9 +740,6 @@ static void restore_exclusive_pte(struct vm_area_struct *vma,
                        pte = pte_mkdirty(pte);
                pte = pte_mkwrite(pte, vma);
        }
-
-       VM_BUG_ON_FOLIO(pte_write(pte) && (!folio_test_anon(folio) &&
-                                          PageAnonExclusive(page)), folio);
        set_pte_at(vma->vm_mm, address, ptep, pte);
 
        /*